Irina Munteanu

Use of intelligent-particle swarm optimization in electromagnetics

The paper describes a new stochastic heuristic algorithm for global optimization. The new optimization algorithm, called intelligent-particle swarm optimization (IPSO), offers more intelligence to particles by using concepts such as: group experiences, unpleasant memories (tabu to be avoided), local landscape models based on virtual neighbors, and memetic replication of successful behavior parameters. The new individual complexity is amplified at the group level and consequently generates a more efficient optimization procedure. A simplified version of the IPSO algorithm was implemented and compared with the classical PSO algorithm for a simple test function and for the Loneys solenoid.

A practical guide to 3-D simulation

This article is intended to give design engineers an overview over some properties of numerical methods used in todays most relevant commercial electromagnetic (EM) simulation tools. It cannot and does not want to be a rigorous analysis of the methods themselves nor a concise description of their history.

Two-step Lanczos algorithm for model order reduction

The Pade-Via-Lanczos (PVL) algorithm proved to be a reliable technique for obtaining reduced-order models of electromagnetic devices. Its computational complexity is, however, quite large, since it involves inversion or factorization of a matrix which can be, for complex devices, on the order of hundreds of thousands. The present paper proposes a two-step approach based entirely on the Lanczos algorithm, meant to drastically reduce the computational complexity. In the first step, a Lanczos-based projection technique is used to reduce the un-inverted matrix to a manageable size, which can be dealt with by the PVL method in the second step. The computing time was thus reduced by a factor of ten, as compared to the classical PVL.

RF & Microwave Simulation with the Finite Integration Technique – From Component to System Design

The paper presents a historical review and the current state-of-the-art of the Finite Integration Technique (FIT), method which has been successfully used for almost 30 years for the solution of electromagnetic field problems. The presented applications are in the range of high-end RF and microwave technologies.

Construction of Differential Material Matrices for the Orthogonal Finite-Integration Technique With Nonlinear Materials

The linearization of an electromagnetic formulation by the Newton method can be expressed similarly as for the linear case, by introducing differential material matrices. For the case of the finite-integration technique applied to an orthogonal grid, the chord material matrix is diagonal whereas the differential material matrices includes off-diagonal bands, representing the cross-directional coupling introduced by the nonlinearity. An approximative Newton method based on a unidirectional differential material matrix yields a diagonal matrix, which has a higher computational efficiency but may lead to a degenerated convergence.

FIT for EMC

The paper describes developments of the finite integration technique (FIT) which offers benefits especially for the EMC community

FIT/PVL circuit-parameter extraction for general electromagnetic devices

The most efficient technique for solving field-circuit coupled problems is to use an equivalent circuit for the electromagnetic device. This paper describes a general technique for determining reduced-order circuits starting from the field equations discretized with the Finite Integration Technique (FIT). Special boundary conditions ensure the good formulation of the coupled problem. Pade Via Lanczos (PVL) techniques are used for reducing the state-space form of the system. The proposed approach eliminates the need to actually solve the field problem in order to extract the parameters of the equivalent circuit.

Triangle Search Method for Nonlinear Electromagnetic Field Computation

This paper presents a hybrid algorithm used, in conjunction with the Finite Integration Technique (FIT), for solving static and quasistatic electromagnetic field problems in nonlinear media. The hybrid technique is based on new theoretical results regarding the similarities between the Picard‐Banach fixed‐point (polarization) method and the Newton method. At each iteration, the solution is obtained as a linear combination of the old solution, and the new Picard‐Banach and Newton solutions. The numerical solutions are calculated through a “triangle” (bidimensional) minimization of the residual or of the energy functional. The goal of this combination is to increase the robustness of the iterative method, without losing the quadratic speed of convergence in the vicinity of the solution. The proposed method generalizes and unifies in a single algorithm the overrelaxed Picard‐Banach and the underrelaxed Newton methods.

Simulation Methodology for the Assessment of Field Uniformity in a Large Anechoic Chamber

The paper presents a simulation methodology for assessing the properties of a generic anechoic chamber, taking into account wall and floor coatings, measurement table, and antenna. Unlike previous approaches, the absorbing walls of the chamber are modeled as infinitely thin sheets. This leads to considerable improvement of the simulation performance. To this aim, a technique for extracting equivalent surface impedance material parameters from wall reflectivity measurements is presented. The large electrical size of the problem, its multiscale character, given by the large dimensions of a typical chamber on one hand and the fine details of the antenna on the other hand, and the complicated material parameters represent the challenges of such a simulation.

A Parallel Electromagnetic Simulation Approach for the Signal Integrity Analysis of IC Packages

A full-wave electromagnetic field simulation based on massive parallelization is proposed as a tool for the signal integrity analysis of complex IC packages. The simulations are based on a specialized domain partitioning method which allows for highly balanced parallel computations. As a real-world example the analysis of a large computer chip spreader is performed Numerical results including signal wave forms and delay times are given.